Transport for London’s decision to open up a wealth of public transport data last week is already paying dividends.

Yesterday saw the launch of a Google Maps mashup that overlays tube trains moving in real time across London. It was developed by Matthew Somerville with help from Frances Berriman and James Aylett and is based on an earlier project in which Matthew attempted something similar with the UK national rail network.

At present there’s little more to the live tube map than to watch the little red dots moving along their lines across the city and say “Wow, isn’t that cool?”. Hopefully Somerville will be able to improve the product by using other Transport for London data to turn it into a powerful resource for Londoners. He’s placed the source code on GitHub to allow others to help work out the kinks.

Maybe he could do a mashup with Betable and let people bet on which train will reach its destination first… or which one will break down and cause commuter chaos first.